What's giving this shady bacteria a new rep

Escherichia coli has a bad rep, but new research reveals how one strain of the bacteria pulls off a pretty cool stunt: annihilating salmonella. Nissle 1917, not to be confused with toxin-containing versions of the microorganism, has long been used to combat diarrhea, but we now know exactly how this all plays out in the intestine, thanks to a study recently published in Cell Host and Microbe.

Basically, Nissle 1917 and salmonella both thrive on iron stores, but this probiotic strain of E. coli is better at taking in the mineral, and hogs available iron. Without iron, salmonella can’t replicate at a high volume, reducing its ability to colonize the gut. In fact, E. coli reduced salmonella levels by more than a hundred-fold in this study, a promising performance in an area where antibiotics don’t make the grade—their bulldozer approach only makes the infection worse by wiping out good bacteria, too.

Although people typically experience salmonella-triggered diarrhea, abdominal cramps, and fever for a few days before recovering, those with more vulnerable immune systems, like older adults and young children, are at risk for more severe manifestations.

“We looked for a bug that could fight for iron better than salmonella can,” says study author Manuela Raffatellu, MD, assistant professor of microbiology and molecular genetics at UC Irvine. “When we understand how bacteria compete with each other, we can design better probiotics.”

This probiotic form of E. coli, which also helps ease Irritable Bowel Syndrome, is available as an over-the-counter pill in Germany, but hasn’t yet hit U.S. drugstores.